Indexes are a very important part of databases and are used
frequently to speed up access to particular data item or items.
So before working with indexes, it is important to understand how
indexes work behind the scene and what is the data structure that
is used to store these indexes, because unless you understand the
inner working of an index, you will never be able to fully
harness its power.

LVM (Logical Volume Management) is a very important tool to have
in the toolkit of a MySQL DBA. It allows you to create and extend
logical volumes on the fly. This allows me to, say, add another
disk and extend a partition effortlessly. The other very
important feature is the ability to take snapshots, that you can
then use for backups. All in all its a must have tool. Hence,
this guide will allow you to understand various terminologies
associated with LVM, together with setting up LVM volumes and in
a later part will also show you how to extend...

We added a 500GB 7.2K SATA/300 Hitachi Deskstar E7K500 16MB disk
to one of our dev servers and partitioned using fdisk and
formatted the partition with etx3. When we tried mounting the
same, we got the following error :

lsof didn’t provide any open files that might be linked to this
problem or there was any “famd” running. Finally doing the
following steps to remove the logical devices from the
device-mapper driver helped us fix the problem.

I’ve been wanting to write a backup script for a while now that
does the following: reads the partition information for the
directory that you are backing up into and computes the
used/available/percentage-available space. Then it reads the
total data size from the MySQL tables and ensures that you have
enough space on disk (for [...]

MySQL Cluster is well known as an in-memory database which can be
restrictive (a server typically has a RAM limit) so it may
surprise some to learn that you can also store MySQL Cluster data
on disk. Disk Data Tables have been in MySQL Cluster for
quite a while, the first GA release with them included was
6.2. They do have caveats which I will describe here, many
of which already have plans to be improved in future
versions.
How Disk Data Tables work

A set of UNDO logs and data files can be created which are on
every data node in the cluster. The UNDO logs bring the
disk data back to a consistent point so that during node …

Every hour, we saw the diskspace on our root partition go up from
45 % to 90 % and come back to 45 %. Initially thought mysql
was processing some temp tables and in the next hour we kept
watching the temp location. In terms of files / diskspace usage
using “du / ls” nothing changed. But lsof provided an interesting
output.

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